A virtual consolidated appliance is a cluster of appliances that work as a single virtual appliance. An appliance can be a server, blade, a rack-mounted server, etc. To distribute workload into the virtual appliance, a current solution is to have a load balancing switch in front of the cluster of appliances to distribute load across them. However, with an L2-L3 load balancing switch, when the administrator tries to add an additional appliance(s) (e.g., to increase processing capacity, or shut down for maintenance, etc.), existing network connections (TCP/UDP/IP) may reset due to the change in the load distribution to the appliances. A similar problem occurs when trying to remove appliances or disable appliances (e.g., for maintenance, power saving, etc.).
A load balancing switch with L4-L7 context can potentially prevent this problem, but adds complexity to the switching logic. Hence, switching speed might suffer. Also this load balancing switch does not work well with redundant switch configuration—active and hot swap—since the context in active switch may not be present when it is replaced by a stand-by.
Thus, techniques which permit existing connections to still be served when a reconfiguration of the virtual consolidated appliance occurs would be desirable.